Remote wireless communications may be implemented using radio frequency (RF) technology. Exemplary applications utilizing RF technology include identification applications including, for example, locating, identifying, and tracking of objects. Radio frequency identification device (RFID) systems have been developed to facilitate identification operations. For example, one device may be arranged to output and receive radio frequency communications and one or more remotely located devices may be configured to communicate with the one device using radio frequency communications. The remotely located device(s) may be referred to as a tag, while the other device may be referred to as a reader. Some advantages of radio frequency communications of exemplary radio frequency identification device systems include an ability to communicate without contact or line-of-sight, at relatively fast speeds, and with robust communication channels.
The assignee of the present invention develops RFID backscatter tags that can be read at extremely long ranges. Various designs are disclosed in patent documents listed below. Some prior RFID tag front end designs have been a compromise between tag receive sensitivity and the quality of backscatter modulation the tag was able to produce due to the choice of the front end component values. For superior tag receive sensitivity, the tag has not been able to produce full depth modulation in some designs. When the tag cannot produce full depth modulation for the length of its entire response to the reader, the tag cannot be read at the maximum distance that would be possible if it did produce full depth modulation for the length of its response. It would be desirable to find a solution to this problem.